TMI - diarrhea at 34 weeks..

So I've had watery diarrhea for the past 3 days at 34 weeks pregnant. Everything I eat goes right through me. I've been trying to eat bland foods (oatmeal, bananas, toast...) but even that goes straight through. I have a dr appt today, but has anyone experienced this? I'm worried it may be my body cleaning out for preterm labor, but idk what that feels like either because I'm a FTM. (Sorry it's not lady-like to speak about these things, but I just want to hear other ladies experiences with this.)